[en] In this study, attempts have been made to utilize biomass residue to recover hydrogen from CH₄ – H₂ gas mixture, which might be applied for hydrocracking process in oil refineries. Part of this attempt is to produce an activated carbon based on coconut shell, which is processed through chemical and physical activation using 25% ZnCl₂ followed by activation at 800°C with N₂ flow for an hour to increase its surface area. The resulted BET surface area and iodine number are 432.26 m²/g and 644.80 mg/g, respectively. A detailed experimental study has been made for the adsorption of pure methane and hydrogen at 20°C, as well as CH₄ – H₂ mixture at 10, 20 and 30°C; each isotherm condition undergoes a variety of pressure ranging from 1 – 6 bars. Measurements were made using volumetric technique and gas chromatograph analysis. The highest adsorption is obtained for pure methane followed by CH₄ – H₂ mixture with 1:9 ratio and pure H₂. For gas mixture, the total adsorption increases with the increase of pressure in each isotherm; in which the higher temperature has lower adsorption ability. The adsorption result shows that methane has 2.7 times higher adsorption capacity than hydrogen and almost all methane in the mixtures is adsorbed by the activated carbon, therefore, the coconut shell based activated carbon produced from this research can be applied as the adsorbent in the separation process of CH₄/H₂ mixture. (paper)

[en] Carbon nanotubes were produced by chemical vapor deposition method to meet the specifications for hydrogen storage. So far, the various catalyst had been studied outlining their activities, performances, and efficiencies. In this work, tri-metallic catalyst consist of Fe-Co-Mo supported on MgO was used. The catalyst was prepared by wet-impregnation method. Liquefied Petroleum Gas (LPG) was used as carbon source. The synthesis was conducted in atmospheric fixed bed reactor at reaction temperature range 750 – 850 °C for 30 minutes. The impregnation method applied in this study successfully deposed metal component on the MgO support surface. It found that the deposited metal components might partially replace Mg(OH)_2 or MgO molecules in their crystal lattice. Compare to the original MgO powder; it was significant increases in pore volume and surface area has occurred during catalyst preparation stages. The size of obtained carbon nanotubes is ranging from about 10.83 nm OD/4.09 nm ID up to 21.84 nm OD/6.51 nm ID, which means that multiwall carbon nanotubes were formed during the synthesis. Yield as much as 2.35 g.CNT/g.catalyst was obtained during 30 minutes synthesis and correspond to carbon nanotubes growth rate of 0.2 μm/min. The BET surface area of the obtained carbon nanotubes is 181.13 m"2/g and around 50 % of which is contributed by mesopores. Micropore with half pore width less than 1 nm contribute about 10% volume of total micro and mesopores volume of the carbon nanotubes. The existence of these micropores is very important to increase the hydrogen storage capacity of the carbon nanotubes.

[en] Adsorption is a separation process that has higher energy efficiency than others. Analyzing the nature of the adsorbate and the selection of suitable adsorbent are key success in adsorption. The performance of the adsorbent can be modified either physically or chemically to obtain the efficiency and effectiveness of the adsorption, this can be facilitated by using a composite adsorbent. In this study, we have conducted the preparation process of a polyvinyl alcohol (PVA)/zeolite/carbon composites. The resulting adsorbent composites are dedicated for ethanol – water dehydration proposes. The composites were prepared using cross-linked polymerization method followed by supercritical fluid extraction (SFE) to obtain the porous structured upon drying process. The characterization of the functional groups and morphology were performed by using Fourier Transform Infra-Red (FTIR) and Scanning Electron Microscopy (SEM), respectively. The FTIR analysis showed that composite prepared by SFE method formed hydrogen bonding confirmed by the appearance of peaks at 2950 – 3000 cm^-1 compared to composite without SFE method, whereas, the results of SEM study showed the formation of three layered structures. On basis of the obtained results, it can be shown that PVA/zeolite/carbon has high potential to be develop further as an adsorbent composite. (paper)